���ճԹ�

‍

University of Cambridge researchers have used human stem cells to create embryo-like structures that replicate aspects of very early human development – including the production of blood stem cells.

The findings  offer ‘a powerful new way’ for studying cancer and immune blood development in the early human embryo, and model blood disorders such as leukaemia.

Human blood stem cells, also known as hematopoietic stem cells, are immature cells that can develop into any type of blood cell, including red blood cells that carry oxygen and various types of white blood cells crucial to the immune system.

The three-dimensional embryo-like structures, which the scientists have named ‘hematoids’, are self-organising and start producing blood after around two weeks of development in the lab – mimicking the development process in human embryos.

St John’s College Research Associate Dr Geraldine Jowett from the University’s Gurdon Institute, joint first author of the new study, said: “Hematoids capture the second wave of blood development that can give rise to specialised immune cells or adaptive lymphoid cells, like T cells, opening up exciting avenues for their use in modelling healthy and cancerous blood development.”

The structures differ from real human embryos in many ways and cannot develop into them because they lack several embryonic tissues, as well as the supporting yolk sac and placenta needed for further development.

Hematoids hold exciting potential for a better understanding of blood formation during early human development, simulating blood disorders such as leukaemia, and for producing long-lasting blood stem cells for transplants.

The human stem cells used to derive hematoids can be created from any cell in the body. This means the approach also holds great potential for personalised medicine, by allowing the production of blood that is fully compatible with a patient’s own body.

Although other methods exist for generating human blood stem cells in the laboratory, these require a cocktail of extra proteins to support the stem cells’ growth and development. The new method mimics the natural developmental process where the cells’ intrinsic support environment drives the formation of blood cells and beating heart cells within the same system.

Dr Jitesh Neupane, co-first author of the study, said: “Our new model mimics human foetal blood development in the lab. This sheds light on how blood cells naturally form during human embryogenesis, offering potential medical advances to screen drugs, study early blood and immune development, and model blood disorders like leukaemia.

“It was an exciting moment when the blood red colour appeared in the dish – it was visible even to the naked eye.”

_{Homepage image: shoma81/Shutterstock}